landing on a comet

Comet 67P/Churyumov–Gerasimenko as seen by Philae lander as it lands on the surface.

Comet 67P/Churyumov–Gerasimenko as seen by Philae lander as it lands on the surface.

The European Space Agency (ESA) has made the first landing on a comet in history with their Rosetta mission. The Philae lander touched down on comet 67P/Churyumov-Gerasimenko at around 11AM EST. Philae will be active for about two days, conducting the first in situ analysis of a comet’s surface. Philae’s mothership will orbit and observe the comet through 2015. The objective of the mission is to observe how a frozen comet is transformed by the sun. Learn more about the Rosetta mission on the ESA’s website.

is ebola evolving?


An electron micrograph of an Ebola virus virion

Is Ebola evolving as it continues to spread throughout parts of Western Africa?  Researchers in the US and Europe face myriad delays as they try to discover the answer. They believe this information is key to understanding how the virus jumps from animals to humans, and also whether it is becoming more virulent or contagious as it continues to spread. According to Science Magazine, thousands of samples have been sitting untouched as scientists await health ministry approvals to import the virus. In places where samples have been imported, scientists have often left the lab for more important field work, helping to contain the virus where they can.

From Science:

Several researchers say that getting export approval from beleaguered health ministries has been tough. “I can only assume that the system is so overwhelmed that processing samples beyond simple diagnostic tests is not high priority,” says Rambaut, who was a co-author on the August sequence paper.

Stephan Günther, a virologist at the Bernhard Nocht Institute for Tropical Medicine (BNI) in Hamburg, Germany, and coordinator of the European Mobile Laboratory (EMLab) consortium, says they have been unable to export samples from Nigeria or Liberia. But BNI has been receiving samples from the EMLab mission in Guinea since March and now has close to 3000, he says. (BNI is storing them in its high-security lab on behalf of the Guinean government, which still owns them.)

Günther and his colleagues have not yet sequenced any of the samples, because consortium staff members have been busy supporting diagnostic centers in affected countries. “We are all busy with fieldwork,” Günther says. “Personnel is a bit of a problem.”

As the global panic eases, clearances should begin. The Institut Pasteur hopes to begin sequencing samples from Guinea soon and samples from Sierra Leone destined for the U.S. were cleared last week. Scientists have also begun making preparations to get DNA sequencers to affected countries. The genome, combined with demographic and treatment information will help provide a clear picture of how the outbreak spread, but there would still be a lot more data needed to determine if Ebola is becoming more virulent:

New sequences probably won’t show that the virus is finding new ways to attack or spread, Rambaut says. Instead, the prize is a clearer picture of the outbreak. A cluster of closely related viruses might point to a hotspot of transmission, he says, while unexpectedly diverse sequences would suggest that many cases were going undetected. Sequence data could also help researchers tell whether there has been more than one animal-to-human introduction.

Earlier sequence data did suggest that the virus was undergoing rapid changes, but that is not necessarily a sign that it is becoming more dangerous, Rambaut says. “Most RNA viruses mutate quickly, but adaptation and functional change is a much slower process.” Measles mutates nearly as quickly as Ebola virus, but it has never evolved to escape the lifelong immunity of previously infected or vaccinated individuals. Even in an outbreak this big, Rambaut says, “I see no reason to suspect the virus will radically change its life cycle or its mode of transmission.”

training your cat

An in-depth study of the cat genome reveals details about their history and behaviors.

An in-depth study of the cat genome highlights a variety of genes, including ones for digesting their meaty diets, keen eyesight and good hearing. The researchers found that pet cats also have genes that allow them to respond to positive reinforcement.  From Popular Science:

Cats also seem to have more genes related to digesting fat than other carnivores do, which is important for their super-meaty diets. (Scientists call cats, including wildcats, hypercarnivores.) Cats even have genes that may help them avoid heart disease from their high-fat diets. Polar bear genomes bear similar markers of selection for fat-digesting genes.

To look for the genes influenced by human selection, the researchers analyzed DNA pooled from 23 pet cats, including Cinnamon. They compared the domestic cat DNA with DNA from four wildcats. Among the feline genetic traits that people seem to have chosen are ones that influence how the cat brain responds to rewards. Yep, that means kitty treats! Mice that are missing the mouse versions of some of those genes are poor at learning with food rewards. Perhaps when people first brought cats into their barns and homes, they chose the ones that were more motivated to do things for people in return for tasty tidbits.

The original research appears in PNAS [subscription required].

hot year

Earth temperature percentiles for September 2014. Dark red patches were record warmest, while lighter red patches were warmer than average. Image courtesy of the NOAA.

Earth temperature percentiles for September 2014. Dark red patches were record warmest, while lighter red patches were warmer than average. Image courtesy of the NOAA.

The trend continues. The hottest September on record follows the hottest August on record, according to data from the Nation Oceanic and Atmospheric Association. 2014 continues apace as the hottest year ever.


An electron micrograph of an Ebola virus virion

An electron micrograph of an Ebola virus virion.

Ebola has been making lots of news this year, as the virus has popped up in several West African countries. We are in the midst of the largest and most widespread outbreak in history.

Fruit bats are the main carriers of the virus in nature. Initially, humans become infected with the ebola virus after contact with infected bats or any living or dead animals that have been infected by the bats. This contact is often thought to be from consumption of infected meat. After humans become infected, the disease spreads through contact with infected bodily fluids including sweat, saliva, urine and semen. Ebola is insidious, and in some cases can take up to 21 days after exposure before symptoms manifest. Symptoms include a sudden onset of flu-like fever, ache and fatigue followed by vomiting or diarrhea.

Sky News details why the virus is so deadly:

When ebola enters the body, it targets dendritic cells in the immune system. Normally, when a virus is detected, these cells tell other cells to produce antibodies. Ebola prevents that signal getting out. As far as the immune system knows, everything inside the body is fine. Left alone, ebola then begins replicating rapidly. It then spreads into the bloodstream, infecting the whole body. Cells start to break up and die, in huge numbers. That finally triggers the immune system, which kicks in – far too aggressively.

Ordinarily when you get sick, the body releases proteins called cytokines. Some of these cells tell your blood vessels to become more permeable. This is to let antibodies travel through the body more quickly to fight the disease. But once ebola has taken hold of your body, the immune system reacts much too aggressively – and launches a cytokine storm. This causes blood vessels to become far too permeable, and they leak. At the same time, the body’s blood clotting mechanisms also act abnormally. This causes internal and external bleeding and is why ebola is known as a haemorrhagic fever. It causes tissue damage and organ failure.

Though the disease is deadly, people do survive and countries can contain outbreaks. Survivors’ blood may contain antibodies that can be used to treat others suffering from the disease.

2014 nobel prizes


The Nobel prizes were awarded this week. Each year there are three science related awards in the fields of medicine, physics and chemistry.

In the field of medicine, the award went to John O´Keefe, May-Britt Moser and Edvard I. Moser for discovering the brain cells that make up our positioning system. In 1971 John O’Keefe discovered that when a rat was in a certain part of the room, one part of the hippocampus was always activated. When the rat was in other parts of a room there were different cells activated. He termed these cells “place cells” and determined that they formed a map. In 2005, the Mosers discovered what they called “grid cells”. These cells generated a coordinate system and aid in finding our way along paths. Read more about the physiology and medicine prize here.

This years physics medal went to the invention of LEDs and was awarded to Isamu Akasaki, Hiroshi Amano, and Shuji Nakamura. The three researchers contributed to the development of LED technology, which is prevalent in today’s telephones, lamps, and computers. LED lights emit brighter light than incandescent lights and for longer periods of time. Read more about the award at Scientific American. The press release is here.

The chemistry prize was awarded to Eric Betzig, Stefan Hell, and William Moerner for developing super resolved fluorescence microscopy. Researchers thought they were limited by the limit of diffraction when it came to resolving images under a microscope. The three Nobel recipients have developed technology that helped overcome this limitation and resolve images into the nanometer scale. Stefan Hell developed a technique called stimulated emission depletion microscopy or STED. Bezig and Moerner, working separately, performed the groundwork for the development of single molecule microscopy. You can read the press release here, and a more detailed description of high resolution microscopy here.